This relates to electronic circuits for providing direct current (dc) isolation.
In the field of electronic signaling, a need occasionally arises for establishing a dc discontinuity between two selected points along a signaling path. This is generally accomplished with capacitors, transformers, relays, or optical isolators. Optical isolators are particularly useful in signal processing applications, such as intercomputer communication paths, because they are small and because their speed of response is high.
One drawback of optical isolators, however, is their relatively low efficiency which results from loss in conversion from electricity to light, loss in dispersal of light, and loss in conversion from light t electricity.
In a separate field of art, dc-to-dc converters are employed to convert a dc voltage of one magnitude to a dc voltage of another magnitude. Such a converter generally includes a high efficiency oscillator for converting the dc input voltage to an ac voltage, a transformer for stepping-up (or stepping-down) the ac voltage, and a rectifier responsive to the stepped-up (or stepped-down) as voltage. In order to obtain a reasonable efficiency, the transformers used in such dc-to-dc converters are generally large and have a core of a relatively high permeability as compared to a core of a relatively high permeability as compared to that of air. Also for sake of efficiency, such dc-to-dc converters generally employ switching oscillators rather than sinusoidal oscillators, and operate them at frequencies below 100 kHz. It should be noted, however, that T. Fujii et al, Electronics, p. 163, Nov. 1, 1957, describes a dc-to-dc converter which employs sinusoidal oscillations in the radio frequency range, and which also employs an air core step-up transformer.
It is an object of this invention to provide a small, inexpensive, efficient, high speed dc (ground) isolating circuit.